Low water pressure with 40 PSI at regulator indicates restriction downstream. Check inline water filter, city water check valve, and any winterization valves. Pump running on city water confirms restriction.
The Dometic Fresh Jet 5 is significantly quieter than the Penguin 2 (about 6-8 dB reduction) and draws similar amps (13-14A). While largely plug-and-play, some wiring modifications may be needed depending on your specific setup.
Code 14 is overspeed but your real issue is carburetor gummed from sitting. Choke mechanism needs cleaning to operate automatically. Clean carburetor thoroughly - jets and choke linkage. Use fresh fuel and add stabilizer to prevent future issues.